Agitator for washing machine



April 18, 1967 T. R. SMITH 3,314,253

GITATOR FOR WASHING MACHINE Filed July 19, 1965 /A/ l/fA/TOAP THOMAS P. SM/7H United States Patent C 3,314,253 AGITATOR FOR WASHING MACHlNE Thomas R. Smith, Newton, Iowa, assignor to The Maytag Company, Newton, Iowa, a corporation of Delaware Filed July 19, 1965, Ser. No. 472,86) 7 Claims. (Cl. 68-18) This invention relates to a novel oscillatable agitator construction useful in a domestic-type clothes washing machine for cleansing fabrics placed within the washing machine and incorporates means for effecting a filtering or dispensing process.

Prior art has shown agitators oscillatably operable in a washing machine to achieve a washing action. These devices, such as the one disclosed in my U.S. Patent 2,976,711, include pump means within the agitator for pumping washing fluids through the agitator to filter out lint and to dispense various washing agents into the washing fiuid. It is shown by prior art that there is a great amount of work being done to discover improved agitator shapes and motions to achieve increased washability.

It is therefore an object of this invention to provide an improved oscillatable agitator useful in a clothes washing machine for achieving increased washability.

It is an additional object of this invention to provide an oscillatable agitator having an improved washing action in a clothes washing machine.

It is a further object of this invention to provide an improved oscillatable agitator operable in a -clothes washing machine for effecting filtering of the washing fluid and dispensing of washing agents into the washing fluid.

It is a further object of this invention to provide an improved oscillatable agitator operable for pumping fiuid through the agitator by providing internal fluid conduits through hollow agitator vanes to replace the conduits defined by pumping vanes usually located within the agitator.

It is still a further object of the present invention to provide an agitator having an improved mode of construction and operation.

It is yet a further object of the present invention to provide a filter agitator operable for producing fiuid flow within the washing container and for utilizing this fluid flow for filtering lint and other foreign objects from the washing fluid.

The present invention achieves these objects with an agitator -construction including an imperforate base having a number of flared portions and a corresponding number of hollow agitating vanes extending upwardly from said base with a hollow centerpost interposed between said vanes. Intake openings are provided for effecting uid flow into the hollow centerpost. A hub construction for oscillating the agitator is provided within said centerpost and is constructed so as to allow the fiuid flow to continue from the centerpost into a plurality of conduits formed cooperatively by the hollow upstanding vanes and an imperforate shroud member having contiguous mating relationship with the underside of said flared portions. The conduits terminate in radially outwardly disposed egress openings communicating with the washing fluid contained within the washing container. It is noted that the shroud member is formed without pumping vanes and that the action of the agitator causes fluid flow through the radially extending conduits formed by the hollow agitating vanes and the shroud member.

Operation of the device and further objects and advantages thereof will become evident as the description proceeds and from an examination of the accompanying drawings which illustrate a preferred embodiment of the invention and in which similar numerals refer to similar parts throughout the several views, wherein:

FIGURE 1 is a perspective view of the agitator construction forming my invention;

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FIGURE 2 is an enlarged fragmentary Vertical sectional view of an oscillatable washing machine agitator construction forming my invention;

FIGURE 3 is a bottom View of the agitator of my invention with the shroud member partially removed to show additional details of the hub structure and hollow agitating vanes.

Referring now to the accompanying drawings in detail, FIGURE l shows an agitator generally indicated by the reference numeral 12 and forming the subject matter of my invention. Agitator 12 includes a lower base portion 14 mounting an agitating structure including hollow agitator vanes 15 and a hollow upstanding cylindrical centerpost 17 having a partition wall portion 16 separating the hollow vane from the hollow centerpost. Centerpost 17 is provided with internal webs 18 which cooperate with each other and with the cylindrical partition wall portion 16 of centerpost 17 to define internal apertures 19, as best shown in FIGURES 2 and 3, and to thereby provide a means of communication between the hollow centerpost 17 and that portion of agitator 12 beneath base portion 14. Y

As previously indi-cated, each of the vanes is hollow and defines a cavity within each vane as best seen in FIGURES 2 and 3. These vanes communicate with the others as will be more fully explained hereinafter, and communicate with the hollow centerpost 17 through internal apertures 19 but are otherwise divided and separated from the hollow centerpost 17 by partition wall portion 15.

The general shape or contour of the vanes is best seen in FIGURES l and 3. It is seen that each vane has a radially outwardly disposed edge 22 including a portion 25 in which the edge 22 extends substantially vertically upward from the base portion 14, and in cooperation with the other vanes, substantially defines a cylinder. Above this portion the vanes include a portion 27 in which the edge or wall intersection 22 tapers toward centerpost 17. The width of the vane, in a horizontal plane adjacent base 14, increases toward the centerpost 17. Each of the agitating vanes joins adjacent vanes with a portion which exceeds the outside diameter of centerpost 17 so as to form a continuous smooth wall 24 extending between edges 22 of adjacent agitating vanes and upwardly from base 14. Wall 24 tapers toward and blends into centerpost 17 at a point approximately midway between the base and the top of the centerpost 17. Edges 22 may also be considered as the intersection of adjacent wall members 24. The thickness of each agitating vane 15 in a vertical plane adjacent centerpost 17 decreases as the vane extends upwardly along centerpost 17.

A vent holes 2S is placed in an uppermost portion of at least one agitating vane for venting the air pocket enclosed within the agitating vanes to the atmosphere. This venting will eliminate the problem of the agitator being floated off or forced upwardly by buoyancy forces.

Webs 1S converge toward the longitudinal axis of center-post 17 to join an inverted cup-shaped agitator driving hub 311 which is connected to the oscillatable driving shaft 32 through a resilient member 34 interconnecting the agitator drive hub 311 and the splined sleeve 35 receiving the agitator drive shaft 32. The oscillatory movement imparted to shaft 32 may be produced by any of the conventional motion converting units now common in the appliance art. Agitator drive shaft 3-2 is journalled in the tub supporting member 37 which c0- operates with the frusto-conical sealin-g washer 38 and clamp nut 39 to form a rigid watertight connection between container 4.0 and mounting member 37. This arrangement provides a satisfactory mounting for a nonrotatable container, such as tub 40, but may, of course,

be revised for a machine having both rotatable and nonrotatable containers.

The upper end of the hollow centerpost 17 is normally covered by a cap member 41 and rigidly connected in turn to the flared upper end of the perforate cylindrical lint filter 42 located within the confines of the hollow centerpost 17 adjacent the slotted Water intake holes 44 'formed in the periphery of the hollow centerpost. The lint liber 42 may include various available screen or mesh constructions for filtering out particles of lint, thread, scum or other foreign particles from the washing fluid flowing through holes 44.

A lip seal 46 encompassing the lower end of the lint filter member 42 and abutting the lower flared extension 45 of lint filter 42 provides a seal between filter 42 and the inside walls of centerpost 17 and thereby prevents lint and other particles from short-circuitin-g filter 42. The entire lint filter assembly lformed by cap 41, lint filter 42 and seal 46 4may be manually removed from the top of centerpost 17 for cleaning and for providing a means to deposit powdered detergent into the hollow centerpost for subsequent dispersion through the agitator assembly into the washing fluid as will be more apparent hereinafter.

It is seen that in the instant embodiment, the vanes 15 divide the base 14 into three flared portions 47. Viewing FIGURE 3, each of these three flared portions extend radially outwardly from substantially upstanding surface 24 and terminate at the circular periphery of the base portion 14.

A flared shroud member 48 conforms generally to the contour of the underside of base portion 14. Shroud member 48 is imperforate except for the centrally located opening 49 and the holes 51 provided at radially outward disposed positions for receiving tapping screws 53 threaded into lugs 54, integrally attached to the underside of base portion 14, for securing shroud member 4S. The flange portion of shroud 48 covers substantially the entire bottom portion of agitator 12 as indicated in FIG- URE 3. The shroud has mating relationship with the th-ree flared portions 47 of agi-tator 1-2 for continuous contact therebetween and encloses the bottom of the hollow vanes 15 to define a plurality of conduits or passageways. These conduits communicate with the upper portion of hollov centerpost 17 through aperture openings 19 and extends to, and terminates at, radially outwardly disposed egress openings 54. It is, therefore, seen that the hollow agitating vanes 15 cooperate with shroud member 4S to provide radially extending conduits for conducting fluid from the apertures 19 through egress openings 56 to the body of fluid within container 40.

This unidirectional fluid flow through the agitator assembly shown in FIGURE 2 is produced by action of the agitator in its oscillatory movement. The action of the agitator vanes imparting a radial thrust on the fluid in addition to the centrifugal force acting upon the water within said conduits formed by the hollow vanes and shroud 48 move the Wate-r through these conduits and outwardly away from egress openings 56 and away from the periphery of the base portion 14 thereby tending to create a reduced fluid pressure at the innermost portions of the substantially radially directed conduits. Such a reduced fluid pressure causes fluid to be taken in through the Water intake holes 44 to equalize fluid pressure. This unidirectional flow continues so long as the agitator 12 is oscillated by means of shaft 32.

An O-ring seal 55 compressed between shroud member 48 a-t the centrally located flanges 58 and the drive hub 31 provides an air seal under shroud member 48 and provides an air-bell effect to prevent water from rising under agitator 12 to a level above the upper surface of tub mounting 37. This protects the agitator drive shaft and its splined connection to the agitator proper as Nell as preventing fluid seepage past the agitator shaft ;eal into the motion converting unit (not shown) for ahaft 32 in the illustrated low center drive construction while permitting the fluid `flow to take place between base portion 14 and shroud member 48.

ln operation, tub 40 is `filled approximately to the level indicated by line AY-A in FIGURE 2 for full tub operation or to some flower level within the elevational range of holes 44 for other than full tube operation. The oscillation of shaft 32 by a conventional drive unit (not shown) causes the agitator vanes '15 to produce the desired washing operation within container 40.

In the preferred embodiment, agitator i12 includes three agitating vanes 15 equally spaced about upstanding centerpost 17. The agitator is preferably caused to oscillate about its axis through an angular arc of approximately It is therefore seen that the angular operation is such that, at the extreme limits of the stroke, a vane will be in the approximate tub position that a space between the vanes occupied at the other end of the stroke.

The oscillation of this agitator within fluid container 40, in coopera-tion with the centrifugal action of the fluid passing through the conduits formed by the hollow agitating vanes 215 and shroud member 48, effects a fluid and fabric movement and cleansing of the fabrics within container 40. The fluid enters the hollow centerpost 17 through intake openings 44 as indicated by arrow 60. Fluid passes through filter 42 and continues through the internal apertures 19 as indicated by arrows 62 and continues into the radially extending pasageways formed by hollow vanes 15 and shroud member 48. The fluid passes through egress opening 56 as indicated by arrow 64 to complete its passage through agitator 12. The water or washing fluid will then tend to take an upward path within washing container 10 and re-enter agitator 12 to repeat the filtering or fluid treatment cycle. The fabrics will tend to take an upward path along the side of container 40 and will move downwardly along the agitator I12 in the general path of the fluid flow. The washing action achieved with this improved agitator construction has been tested for relative washability and found to be an improvement over existing designs. This improved washability is particularly outstanding when washing relatively large loads.

The oscillation of vanes 15 also normally causes a separation of lint particles from the fabrics being washed within the fluid contained within the tub 40 and causes these particles to circulate within the body of the fluid and becomes deposited on other fabrics unless they are separated from the washing fluid. The circulation of the fluid within the container 40 as previously described Causes washing fluid to enter the water intake openings 44 and carry the particles of lint, thread or other foreign particles suspended within the washing fluid through the hollow centerpost 17.

These Iparticles are filtered from the Washing fluid entering centerpost 17 by means of the cylindrical lint filter assembly 42 which retains the filtered particles on its periphery while permitting the filtered fluid to pass downwardly through the hollow post 17 to enter the apertures 19 and pass through the radially extending passageways.

Upon termination of movement of agitator 12, the lint filter 42 may be removed from the centerpost 17 by grasping cap 41 and lifting it from centerpost 17. This action allows the self-biased lip seal 46 to scrape free any particles or sediment accumulating upon the inner surface of centerpost 17.

The agitator assembly may also be used to gradually disperse powdered detergent into the fluid by providing a funnel-shaped opening within cap 41 or by merely removing the lint filter assembly formed by elements 41, 42 and 46 and inserting the desired quantity of powdered detergent into the detergent charging chamber 68 within centerpost 17. The lint lter assembly may then be replaced within centerpost 17 prior to the filling of container 40. The loading of the powdered detergent into centerpost 17 in this manner allows the detergent to be gradually dissolved at a point isolated from the fabrics being washed and then to be dispersed through the passageways formed by the cooperation of vanes and shroud member 48 during the tub filling and initial agitation operation without directly coming into contact with the fabrics placed within container 4G. The gradual dispersement of detergent in this manner prevents concentrated quantities of detergent from tending to weaken or deteriorate the fabric fibers being cleaned. lt should be noted that other types of washing additive dispensers may be used in association with this agitator for using the fluid entering intake openings 44 and thereby dispersing the Awashing agent within container 40 gradually and without immediate contact with the fabric being washed.

While the relative sizes of the openings in the passageways formed within this filter agitator assembly prevent the detergent inserted into centerpost 17 from flowing rapidly out these passageways, tests have shown that the unidirectional fluid flow through this agitator assembly successfully flushes these passageways clean during the agitation operation without producing accumulated detergent deposit formations in these passageways.

In addition to the improved washability, this new agitator construction achieves other advantages. The hollow vane construction provides relatively massive vanes for the effective washing action with a minimum of material and weight while providing internal conduits to facilitate elimination of the pumping vanes from the shroud member as has been used in previous designs.

In summary, it may therefore be stated that my proposed agitator provides an improved construction which is effective for producing the improved washing `action and increased washability. This increased washability is maintained even with large loads of clothing being washed. My proposed agitator construction includes a means for filtering lint, thread and other foreign particles from the washing fluid contained within the container. This agitator includes a novel arrangement of pumping conduits defined by the hollow vanes and a shroud member. This pumping action and clothes washing action is obtained at no expense to the air bell required to prevent water from entering the low center drive construction for the illustrated type of machine. This is an agitator which is effective for achieving optimum washability while providing useful means for dispersing washing agents into the washing fluid.

In the drawings and specification, there has been set forth a preferred embodiment of the invention and, although specic terms are employed, there are used in a generic and descriptive sense only, and not for purposes of limitation. Changes in form and the proportion of parts, as well as the substitution of equivalents are contemplated, as circumstances may suggest or render expedient, without departing from the spirit or scope of this invention as further defined in the following claims.

I claim:

1. An agitator assembly adapted to be submerged in a body of washing fluid and oscillatable therein to effect a cleansing of fabrics within said fluid, the combination comprising: a base member having flared portions disposed about a central axis; a centrally located fluid agitating structure mounted on said base member, said agitating structure including a plurality of wall members extending generally upward from said flared portions and joining with adjacent wall members to define a plurality of lhollow agitating vanes; a centrally located hollow centerpost interposed between said agitating vanes and including a partition portion between said hollow centerpost and said hollow agitating vanes; a plurality of fluid intake openings in said centerpost providing a means for fluid flow into said centerpost from said body of fluid; a hub portion positioned within said centerpost; a plurality of webs interconnecting said centerpost and said hub portion and defining a series of internal apertures between said centerpost and said hub portion; a shroud member connected to the underside of said base member and extending inwardly to said hub portion, said shroud member including first portions mating with the underside of said flared portions for preventing fluid flow between said flared portions and said first portions and further including a second portions cooperable with said wall members for defining a plurality of conduits through said agitating vanes communicating with said internal apertures and terminating in radially outwardly disposed egress openings; and fluid treatment means positioned within said hollow centerpost in the path of fluid flow through said agitator, said hub portion being adapted to receive an agitator shaft for oscillating said agitator and thereby effecting a unidirectional fluid flow therethrough.

2. An agitator assembly adapted to be submerged in a body of washing fluid and oscillatable therein to effect a cleansing of fabrics within said fluid, the combination comprising: a base member having flared portions disposed about a central axis; hollow agitating vanes extending upwardly from said base member between said flared portions; a centrally located hollow centerpost interposed between said hollow vanes, said hollow vanes including an upper portion tapering toward said centerpost; a plurality of fluid intake openings in said centerpost providing a means for fluid flow into said centerpost from said body of fluid; a hub portion positioned within said centerpost; a plurality of webs interconnecting said centerpost and said hub portion and dening a series of internal apertures between said centerpost and said hub portion; a shroud member connected to the underside of said base member and extending inwardly to said hub lportion, said shroud member including rst portions mating with the underside of said flared portions for preventing fluid flow therebetween and further including second portions cooperable with said hollow vanes for defining a plurality of conduits through said hollow vanes communieating with said internal apertures and terminating in radially outward disposed egress openings to said body of fluid; and fluid treatment means positioned within said hollow centerpost in the path of fluid flow through said agitator, said hub portion being adapted to receive an agitator shaft for oscillating said agitator and thereby effecting a unidirectional fluid flow through said agitator to effect a treatment of the fluid passing therethrough.

3. In a washing machine embodying the agitator assembly of claim 2 and further embodying means for oscillating said agitator through a predetermined arc sufficient to move said agitating vanes between a first position at one end of a stroke and a second position at the other end of said stroke, said second position being the position of said flared portions when said agitating vanes are in said first position.

4. An agitator assembly adapted to be submerged in a body of washing fluid and oscillatable therein to effect a cleansing of fabrics within said fluid, the combination comprising: a base member having irnperforate flared portions disposed about a central axis; a centrally located fluid agitating structure mounted on said base member, said agitating structure including a concave wall member having a relatively large radius of curvature in a plane perpendicular to said central axis and extending generally upward from each of said flared portions and joining with adja-cent wall members to define a plurality of hollow agitating vanes extending radially between adjacent flared portions; a centrally located hollow centerpost interposed between said hollow agitating vanes and including apartition portion between said hollow centerpost and said hollow vanes; a plurality of fluid intake openings in said centerpost disposed between adjacent vanes and providing a means for fluid flow into said centerpost from said body of fluid; a hub portion positioned within said centerpost; a plurality of webs interconnecting said centerpost and said hub portion and defining a series of internal apertures between said centerpost and said hub portion; a shroud member connected to the underside of said base member and extending inwardly to said hub portion, said shroud member including first portions mating with the underside of said flared portions for preventing7 fluid flow therebetween and further including second portions cooperable with said wall members for defining a plurality of conduits through said hollow vanes communicating with said internal apertures and terminating in radially outward disposed egress openings; and fluid treatment means positioned within said hollow centerpost in the path of fluid flow through said agitator, said hub portion being adapted to receive an agitator shaft for oscillating said agitator and effecting a unidirectional :fluid flow through said agitator.

5. An agitator assembly adapted to be submerged in a body of washing fluid and oscillatable therein to effect a cleansing of fabrics within said fluid, the combination comprising: a base member having imperforate flared portions disposed about a central axis; hollow agitating vanes extending upwardly from said base member between said flared portions and joining with adjacent agitating vanes to form a concave surface extending from a radially outward disposed edge of each agitating Vane to the corresponding edge of an adjacent vane; a centrally located follow centerpost interposed between hollow agitating vanes and including a partition portion between said hollow centerpost and said hollow agitating vanes, said agi- :ating vanes including an upper portion having decreasing :hickness and tapering toward said centerpost in the upvard direction; a plurality of fluid intake openings in said :enterpost disposed between said agitating vanes and pro- /iding a means for fluid flow into said centerpost from ;aid body of fluid; a hub portion positioned within the ,ower regions of said centerpost; a plurality of webs inerconnecting said centerpost and said hub portion and lefining a series of internal apertures between said cenerpost and said hub portion; a shroud member connected vo the underside of said base member and extending in- Wardly to said hub portion, said shroud member includng first portions mating with the underside of said flared )ortions for preventing fluid flow therebetween and furyher including second portions cooperable with said holow vanes for dening a plurality of conduits through said follow vanes communicating with said internal apertures ind terminating in radially outward disposed egress openngs; and fluid treatment means positioned within the up- Jer regions of said hollow centerpost in the path of fluid low through said agitator, said hub portion being adapted o receive an agitator shaft for oscillating said agitator md thereby effecting a unidirectional fluid flow through `aid agitator to effect the treatment of the fluid passing herethrough.

6. An agitator assembly adapted to be submerged in a iody of washing fluid and oscillatable therein to effect a :leansing of fabrics within said fluid, the combination :omprising: a base member having flared portions disaosed about a central axis; radially positioned hollow tgitating vanes extending upwardly from said base mem- )er between said flared portions and including a pair of `ide wall members increasingly spaced apart toward said `entral axis, said wall members being thereby disposed tt an angle to the radial centerline of said agitating vanes 'or imparting a radial force to said fluid upon oscillation of said agitator; a centrally located hollow centerpost interposed between said agitating vanes; a plurality of fluid intake openings in said centerpost providing a means for fluid flow into said centerpost from said body of fluids; a hub portion positioned within said centerpost; a plurality of webs interconnecting said centerpost and said hub portion and defining a series of internal apertures beextending inwardly to said hub portion, said shroud member connected to the underside of said base member and extending inwardly to said hub protion, said shroud member including first portions mating with the underside of said flared portions for preventing fluid flow therebetween and further including second portions cooperable with said hollow vanes for defining a plurality of conduits through said hollow vanes communicating with said internal apertures and terminating in radially outward disposed egress openings; and fluid treatment means positioned within said hollow centerpost in the path of fluid flow through said agitator, said huh portion being adapted to receive an agitator shaft for oscillating said agitator.

7. An agitator assembly adapted to be submerged in a body of washing fluid and `oscillatable therein to effect a cleansing of fabrics within said fluid, the combination comprising: a base member having flared portions disposed about a central axis; a centrally located fluid agitating structure mounting on said base member, said agitating structure including a Wall member extending generally upward from each of said flared portions and joining with adjacent wall members to define a plurality of downwardly opening hollow agitating vanes; an upwardly opening centrally located hollow centerpost interposed between said hollow agitating vanes; a plurality of fluid intake openings in said centerpost providing a means for fluid flow into said centerpost from said body of fluids; a hub portion positioned within the lower region of said centerpost to receive means operable for oscillating said agitator within said washing fluid; a plurality of webs interconnecting said centerpost and said hub portion and defining a series of internal apertures for effecting uid flow from said hollow centerpost; a shroud member connected to the underside of said base member and extending inwardly to said hub portion, said shroud member including first portions mating with the underside of said flared portions for preventing fluid flow therebetween and further including second portions covering a major inner portion of said downwardly opening hollow agitating vanes for defining a plurality of conduits through said agitating vanes communicating with said internal apertures and terminating in radially outwardly disposed egress openings; and fluid treatment means positioned within said hollow centerpost in the path of fluid flow through said agitator.

References Cited by the Examiner UNITED STATES PATENTS 2,042,578 6/1936 Behan 68-134 2,498,894 2/1950 McCormick et al 68-17 2,916,900 12/1959 Gearhardt et al 68-18 2,976,711 3/1961 Smith 68-17 IRVING BUNEVICH, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE.- OF CORRECTION Patent Nm 3,314,253 April 1s, 1967 Thomas R, Smith It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as Corrected below.

Column 2 line 52, for l'holes" read hole Column 3 line 9, for "fiber" read filter line 67, for "flanges" read flange column 4, line 6, for "tube" read tub line 46, for "becomes" read become column 5, line 48 for "there" read these Column 6, line 5, strike out "a"; Column 8 line 8 strike out "extending inwardly to said hub portion, said" and insert instead tween said centerpost and said hub portion; a Q

Signed and sealed this 28th day of November 1967 SEAL) ttest:

Edward M. Fletcher, Jr. EDWARD BRENNER testing Officer Commissioner of Patents 

2. AN AGITATOR ASSEMBLY ADAPTED TO BE SUBMERGED IN A BODY OF WASHING FLUID AND OSCILLATABLE THEREIN TO EFFECT A CLEANSING OF FABRICS WITHIN SAID FLUID, THE COMBINATION COMPRISING: A BASE MEMBER HAVING FLARED PORTIONS DISPOSED ABOUT A CENTRAL AXIS; HOLLOW AGITATING VANES EXTENDING UPWARDLY FROM SAID BASE MEMBER BETWEEN SAID FLARED PORTIONS; A CENTRALLY LOCATED HOLLOW CENTERPOST INTERPOSED BETWEEN SAID HOLLOW VANES, SAID HOLLOW VANES INCLUDING AN UPPER PORTION TAPERING TOWARD SAID CENTERPOST; A PLURALITY OF FLUID INTAKE OPENINGS IN SAID CENTERPOST PROVIDING A MEANS FOR FLUID FLOW INTO SAID CENTERPOST FROM SAID BODY OF FLUID; A HUB PORTION POSITIONED WITHIN SAID CENTERPOST; A PLURALITY OF WEBS INTERCONNECTING SAID CENTERPOST AND SAID HUB PORTION AND DEFINING A SERIES OF INTERNAL APERTURES BETWEEN SAID CENTERPOST AND SAID HUB PORTION; A SHROUD MEMBER CONNECTED TO THE UNDERSIDE OF SAID BASE MEMBER AND EXTENDING INWARDLY TO SAID HUB PORTION, SAID SHROUD MEMBER INCLUDING FIRST PORTIONS MATING WITH THE UNDERSIDE OF SAID FLARED PORTIONS FOR PREVENTING FLUID FLOW THEREBETWEEN AND FURTHER INCLUDING SECOND PORTIONS COOPERABLE WITH SAID HOLLOW VANES FOR DEFINING A PLURALITY OF CONDUITS THROUGH SAID HOLLOW VANES COMMUNICATING WITH SAID INTERNAL APERTURES AND TERMINATING IN RADIALLY OUTWARD DISPOSED EGRESS OPENINGS TO SAID BODY OF FLUID; AND FLUID TREATMENT MEANS POSITIONED WITHIN SAID HOLLOW CENTERPOST IN THE PATH OF FLUID FLOW THROUGH SAID AGITATOR, SAID HUB PORTION BEING ADAPTED TO RECEIVE AN AGITATOR SHAFT FOR OSCILLATING SAID AGITATOR AND THEREBY EFFECTING A UNIDIRECTIONAL FLUID FLOW THROUGH SAID AGITATOR TO EFFECT A TREATMENT OF THE FLUID PASSING THERETHROUGH. 